THE  LIBRARY 

OF 

THE  UNIVERSITY 
OF  CALIFORNIA 

LOS  ANGELES 


GIFT  OF 


Mrs.  Clifford  B.  Walker 


THE  LIBRARY 

UNIVERSITY  OF  CALIFOBNIA 
LOS  ANGELES 


STEREOSCOPIC  TREATMENT 

OF 

HETEROPHORIA  AND  HETEROTROPIA 

Designed  to  Accompany  the  Phoro-optometer 

Stereoscope  and  the  Wells  Selection 

of  Stereoscopic  Charts 


By 
DAVID  W.  WELLS,  M.D. 

'  Member  of  A.  M.  A.  and  A.  I.  H. 

Associate  Professor  of  Ophthalmology,  Boston  University  Medical  School 
Ophthalmic  Surgeon,  Massachusetts  Homoeopathic  Hospital,  Boston 

Oculist,  Newton  (Mass.)  Hospital 
Author  of  "Psychology  Applied  to  Medicine" 


New  York 

E.  B.  MEYROWITZ,  Publisher 
1912 


Copyright,  1912,  by 
E.  B.  Meyrowitz,  New  York 


Library 

WIO 


PREFACE. 

I      \  I  Ut  - 

CONCERNING  the  clinical  importance  of  hetero- 
phoria  ophthalmologists  are  not  agreed.  As  a 
protest  against  the  extravagant  claims  made  by 
some  enthusiasts,  there  has  arisen  a  class  of 
eminent  practitioners  whose  members  abso- 
lutely ignore  the  subject  and  omit  all  tests  for 
imbalance,  unless  there  exists  actual  hetero- 
tropia.  The  author  believes  he  occupies  a 
middle  ground,  and  that  the  opinions  herein 
expressed  are  conservative. 

The  orthoptic  treatment  of  heterotropia  is  not 
always  successful,  but  there  is  a  growing  con- 
viction that  the  surgeon  who  rests  content  with 
securing  a  cosmetic  cure  has  not  discharged  his 
whole  duty  to  his  patient. 

It  is  unfortunately  still  true  that  the  majority 
of  heterotropic  cases  are  not  seen  by  the  oph- 
thalmologist until  the  condition  is  quite  firmly 
established.  No  opportunity  should  be  lost  to 
warn  the  family  physician  that  the  time  to  begin 
treatment  is  the  minute  the  deviation  is  noticed. 

Believing  that  the  cases  of  heterophoria 
requiring  relief  are  much  more  numerous  than 
those  of  actual  heterotropia,  the  greater  part 
of  this  essay  will  be  devoted  to  the  former  con- 
dition. 


635953 


IV  PREFACE. 

For  the  benefit  of  the  beginner  in  ophthal- 
mology a  brief  summary  is  given  of  the  impor- 
tant points  of  binocular  vision,  the  factors  upon 
which  depends  orthophoria,  the  causes  of  het- 
erophoria,  and  a  discussion  of  the  different 
methods  of  testing.  While  the  treatment  IKK 
presented  is  principally  stereoscopic  fusion 
training,  other  adjuvants  are  advised.  The 
stereoscopic  method  is  outlined  with  consider- 
able detail,  and  is  the  result  of  several  years' 
experience.  It  is  earnestly  hoped  that  many 
others  may  find  in  the  phoro-optometer  stereo 
scope  and  the  charts  here  described  that  same 
degree  of  satisfaction  which  they  afford  to  the 
author. 

If  the  instructions  seem  more  didactic  than 
is  consistent  with  good  taste,  he  can  only  plead 
that  he  is  attempting  to  lay  before  the  reader 
his  own  method,  and  would  gladly  welcome  any 
suggestions  for  improving  it. 

Believing  that  the  limitations  of  the  orthoptic 
treatment  of  heterotropia  should  be  thoroughly 
understood,  the  indications  for  operative  inter 
ference  have  been  briefly  stated. 

D.    W.    \V. 
HOTEL   WESTMINSTER,   COPLEY   SQUARE.   BOSTON.     .Fan..   I'.H-J. 


CONTENTS. 


PAGE 

CHAPTER  1 7 

Binocular  Vision — Law  of  Corresponding  Points — 
Semi-decussation — Fusion  Faculty. 

CHAPTER   II 12 

Ortliophoria  —  Heterophoria  —  Stevens'  Photometer — 
Savage's  Monocular  Phorometer  —  Wells'  Handy 
Phorometer — Prentice  Prismometer  and  Phoro- 
meter— Screen  Test — Duction — Causes  of  Hetero- 
phoria— Symptoms  of  Heterophoria. 

CHAPTER    III 23 

Treatment  of  Heterophoria  —  Prismatic  Glasses  — 
Operative — Muscle  Training — Fusion  and  Muscle 
Training — Phoro-optometer  Stereoscope. 

CHAPTER    IV 32 

Stereoscopic  Treatment  of  Exophoria — Author's  Card 
for  Measurement  of  Stereoscopic  Heterophoria — 
Amplitude  of  Fusion — Recovery  Exercises — Home 
Exercises — The  Suppressed  Eye — Controlled  Read- 
ing— Author's  Device — Number  of  Cases  Treated 
and  Results. 

CHAPTER   V 54 

Stereoscopic  Treatment  of  Esophoria — May  Be  an 
Expression  of  Convergence  Insufficiency — Fusion 
Training  Same  as  for  Exophoria — Amplitude 
Training  the  Reverse  or  May  Be  Same  as  for 
Exophoria. 

(v) 


VI  CONTENTS. 


I'AUK 


CHAPTER  VI 59 

Treatment  of  Hyperphoria — Stereoscopic  Treatment 
Not  Practicable — Prism-duction  Treatment — Au- 
thor's Cards  for  Right  and  Left  Hyperphoria. 

CHAPTER   VII 62 

Stereoscopic  Treatment  of  Heterotropia — of  Concomi- 
tant Esotropia  —  The  Amblyoscope  —  Autlim  '- 
Deviometer — The  Percentage  of  Cures — The 
Time  for  Operation — Treatment  jf  Alternating 
Esotropia — Treatment  of  Exotropia. 


CHAPTER    VIII. 


Concluding  Remarks — Theories — Psychic  Element — 
The  Choice  of  Cards — Superabundance  of  Ampli- 
tude a  Valuable  Reserve. 


CHAPTER  I. 

BINOCULAR    VISION.  — LAW    OF    CORRESPONDING 
POINTS.  —  SEMI-DECUSSATION .  —  FUSION  FACULTY. 

BINOCULAR  single  vision  is  a  rather  intricate 
psychic  faculty  dependent  on  certain  exact 
physical  conditions.  "With  each  eye  we  see  a 
separate  object  and,  according  to  the  law  of 
corresponding  points,  it  is  necessary  that  the 
images  of  the  object  fall  upon  corresponding 
points  of  the  two  retinae  in  order  that  single 
binocular  vision  may  be  realized.  For  central 
vision  these  points  are  the  two  maculae,  and  for 
peripheral  vision  these  points  must  be  equally 
to  the  right,  to  the  left,  above  or  below  the  two 
maculae. 


LEFT 


EIGHT 


FIG.   1. — CORRESPONDING  RETINAL  POINTS. 


(LE  CONTE.) 
(7) 


8  STEREOSCOPIC    TREATMENT    OF 

The  field  of  binocular  single  vision  is  that 
portion  of  the  two  fields  which  can  be  seen  by 
both  eyes  simultaneously,  the  projection  of  a 
single  impression  depending  upon  the  seini- 
decussation  of  the  fibers  of  the  optic  nerve, 
which  occurs  only  in  man  and  the  higher  apes. 
Semi-decussation  is,  therefore,  the  first  physical 
essential. 


FIG.  2. — SEMI-DECUSSATION  OF  OPTIC  NERVE. 

To  explain  this,  and  the  clinical  facts  of  homi- 
anopsia,  it  is  assumed  that  at  the  chiasm  each 
neuron  divides  into  two,  one  of  which  crosses 
to  the  nasal  side  of  the  opposite  eye,  while  the 
other  goes  to  the  temporal  side  of  the  eye  on 
the  same  side,  the  end  organs  occupying  corre- 
sponding points  in  the  two  retinas. 

A  second  physical  requisite  is  the  perfect 
coordination  of  the  twelve  extrinsic  muscles. 


HETEEOPHORIA   AND    HETEROTROPIA.  9 

that  the  eyes  may  be  so  directed  to  any  point 
in  the  binocular  field,  that  the  images  shall  fall 
on  corresponding  points. 

AVlien  it  is  realized  that  a  deviation  of  less 
than  a  millimeter*  in  the  position  of  correspond- 
ing points  means  diplopia  for  small  objects,  it 
is  almost  inconceivable  that  any  mechanics  alone 
could  secure  the  desired  result.f 

THE    FUSION    FACULTY. 

According  to  Worth,  sight  in  the  newborn  is 
limited  to  fixation  of  a  light  so  that  all  the  finer 
qualities  are  the  result  of  personal  experience. 
The  involuntary  movements  of  the  eyes  of 
infants  would  show  that  there  is  no  conception 
of  binocular  vision.  The  full  development  of 
the  fusion  faculty  is  not  attained  till  the  fifth 
or  sixth  year  with  the  normal  child. 

Physiological  diplopia  means  that  objects 
nearer  or  farther  than  the  point  fixed  are 


'According  to  Suter:  "Refraction  and  Motility  of  the  Eye," 
page  142.  "The  fovea  centralis,  upon  which  falls  the  image 
of  every  object  attracting  mental  attention,  does  not  exceed 
0.4  mm.  in  diameter."  Taking  the  distance  of  the  nodal 
point  in  front  of  the  retina  to  be  15  mm.  Dennett,  of  New 
York,  has  shown  by  theorem  of  similar  triangles,  that,  at 
n  distance  of  one-half  meter,  an  object  to  be  discerned  with 
normal  acuity  cannot  exceed  13.5+  mm.  in  diameter. 

fSanford:    "Experimental    Psychology,"    page    106. 


10 


STEREOSCOPIC    TREATMENT    OF 


always  seen  double,  but  the  adult  has  so  far 
succeeded  in  ignoring  this,  that  it  is  sometimes 
difficult  to  make  him  realize  the  doubling. 


Fiu.    3. — PHYSIOLOGICAL    DIPLOPIA    OF   OBJECTS    FABTHEB  OB 
NEAREB  THAN    NIK  POINT  FIXKD. 

THERE  can  be  little  doubt  that  this  fact  plays 
a  very  important  role  in  the  child's  experience, 
the  fusing  at  different  distances  developing  the 
idea  of  perspective.  Omitting  tlie  few  cases  of 
congenital  defect,  strabismus,  better  c-illed 
heterotropia,  if  we  adopt  the  more  recent 
nomenclature,  begins  between  the  ages  of  one 
and  four,  a  time  during  which  the  fusion  faculty 
should  be  developing.  The  significance  of  this 
fact  in  the  treatment  of  this  condition  has  been 


HETEROPHOEIA   AND    HETEROTROPIA.  11 

so  ably  presented  by  Worth  that  the  reader  is 
referred  to  his  classic  treatise  on  Squint. 

The  argument  is  here  introduced  to  emphasize 
the  fact  that  the  third  essential  to  binocular 
single  vision  is  the  psychic  one  of  the  fusion 
faculty.  Without  such  an  overruling  guid- 
ance the  necessarily  exact  coordination  is  incon- 
ceivable. 

A  discussion  of  the  academic  question  of  the 
existence  of  a  fusion  center  is  not  essential  to 
our  purpose,  and  those  interested  are  referred 
to  Savage,  "Ophthalmic  Myology, "  and  "Oph- 
thalmo-neuro-myology " ;  Duane,  "The  Extra 
Ocular  Muscles,"  in  Posey  &  Spiller's  "Eye 
and  Nervous  System." 

The  frequent  clinical  experience,  that  loss  of 
sight  of  one  eye  is  frequently  followed  by  diver- 
gence, is  an  unanswerable  argument  for  the  im- 
portance of  the  fusion  faculty  in  keeping  eyes 
straight  and  it  is  the  purpose  of  this  writing  to 
show  that  it  plays  quite  as  important  a  part  in 
the  production  and  the  cure  of  those  tendencies 
to  turn,  grouped  under  the  name  heterophoria. 
Even  Stevens,  who  did  such  pioneer  work  in 
calling  attention  to  heterophoria  as  a  cause  of 
asthenopia  and  reflex  nervous  disturbances,  has 
devoted  himself  entirely  to  the  physical  side  of 
the  subject. 


12  STEREOSCOPIC    TREATMENT    OF 


CHAPTER  II. 

ORTHOPHORIA.  —  HETEROPHORIA.  — STEVENS*  PHORO- 
METER.— SAVAGE'S  MONOCULAR  PHOROMKTKK. 
-WELLS'    HANDY    PHOROMETER.— PHKN  n<  i 
WILLIAMS'  PRISOMETER.— SCREEN  TEST.— i> 

TION.  —  CAUSES  OF  HETEROPHORIA.  —  SYMPTOM > 
OF  HETEROPHORIA. 

ORTHOPHORIA— right  tending— is  the  condition 
where  both  eyes  tend  to  look  at  the  same  point 
at  all  distances.  Those  who  believe  in  the  <li> 
turbing  influence  of  kataphoria  and  anaphoria 
would  dissent  from  calling  this  a  condition  of 
perfect  muscle  balance.  While  orthophoria 
necessitates  normal  orbits,  proper  strength/  in- 
sertion and  nerve  supply  of  muscles,  it  is  also 
influenced  by  other  factors.  Sight  requires  ac- 
commodation for  all  distances  from  ten  inches 
to  infinity,  and  fixation  of  the  two  e/es  upon  this 
spot.  This  is  a  most  beautiful  example  of  coor- 
dination, but  is  easily  disturbed  by  an  abnor- 
mality of  accommodation,  which  may  be  in  the 
ciliary  muscle  itself,  or  in  a  refractive  error 
which  necessitates  abnormal  accommodation  for 
its  correction. 

It  therefore  follows  that  muscle  tests  should 
be  made  with  the  patient  wearing  his  correcting 


HETEROPHOEIA   AND    HETEROTROPIA.  13 

glasses,  and  also  without,  so  that  the  influence 
of  the  refractive  error  may  be  determined.  As 
absolute  perfection  is  not  to  be  expected,  it  would 
be  advisable  to  adopt  a  minimum  error  which 
might  still  allow  the  classification  orthophoria. 

HETEROPHOEIA— cross  or  wrong  tending— is 
the  condition  of  most  of  the  human  family  if 
sufficiently  careful  tests  are  made.  It  would, 
therefore,  be  desirable  to  adopt  some  standard 
which  recognizes  a  minimum  of  error  to  warrant 
the  term  heterophoria. 

Only  the  principal  forms,  esophoria,  tendency 
in;  exophoria,  tendency  out,  and  hyperphoria, 
tendency  of  one  above  the  other,  will  be  here 
considered.  Cyclophoria,  a  twisting  tendency; 
anaphoria,  a  tendency  of  both  eyes  above  the 
normal  level;  kataphoria,  a  tendency  of  both 
eyes  below  the  normal  level,  are  conditions 
which  the  writer  does  not  feel  qualified  to  dis- 
cuss, much  less  to  treat  stereoscopically. 

METHODS  OF  TESTING. 

Stevens'  phorometer  is  probably  most  univer- 
sally used.  Savage  objects  to  this  method  be- 
cause both  images  are  artificially  displaced. 

The  Savage  monocular  phorometer  consists 
of  a  rotary  prism  and  a  displacing  prism  before 


14 


STEREOSCOPIC    TREATMENT    OF 


the  same  eye.  This,  he  says,  prevents  the  eye 
which  is  in  the  primary  position  from  partici- 
pating. 

The  same  result  is  obtained  with  the  Wells' 
handy  phorometer,  which  consists  of  a  si i mit- 
ten-diopter prism  and  a  weighted  disc. 


FIG.  4. — WELLS'  HANDY  PHOROMETEB. 


When  the  prism  is  tilted  till  the  double  images 
are  horizontal  or  vortical  the  index  on  the  disc 
indicates  the  amount  and  kind  of  heterophoria. 
This  instrument  is  not  intended  to  measure  frac- 
tions of  a  prism  diopter. 

The  Maddox  rod  is  a  very  accurate  test.  A 
test  which  diagnoses  and  measures  the  error  at 


HETEEOPHOKIA    AND    HETEEOTEOPIA.  15 

the  same  time  is  one  devised  by  Charles  F. 
Prentice,  of  New  York,  in  1890.  It  is  based  on 
the  principle  that  a  prism  of  1A  causes  a  devia- 
tion of  1  cm.  at  1  m.,  5  cm.  at  5  m.,  etc.  It  is, 
therefore,  constructed  for  any  distance,  5  or 
6  m.* 

o 

o 
o 
o 
o 


o 
o 
o 
o 
o 

FIG.  5. — PRENTICE  PRISMOMETEB  AND  PHOROMETER. 

The  Wells  apparatus,  which  has  been  in  use 
since  1891,  is  copied  from  Prentice  and  consists 
of  lights  1  cm.  diameter,  5  cm.  between  centers, 
on  the  wall  5  m.  from  the  patient. 

*  Prentice:  "Ophthalmic  Lenses" — Shows  that  for  exact 
tangent  measurement  of  prism  diopters,  a  6  m.  distance  is 
essential. 


1l'>  STKKKOSCOPIC    TIII.A  I  M  I.NT    or 

Vertical  lights  are  green— horizontal  lights 
red.  Patient  is  armed  with  red  ulass  In-fore  one 
eye  of  sufficient  color  to  obscure  the  green. 
green  glass  before  the  other  eye  of  sutlicient 
depth  of  color  to  obscure  the  red.  If  red  pi. 
be  before  right  ami  irreeii  before  left,  right  eye 
will  sec  horizontal  red  lights  ami  left  eye  verti- 
cal green  lights. 

Tf  orthophoria  exists  a  perfect  cross  will  be 
seen  as  if  both  the  colors  were  seen  by  one  eye. 
If  exophoria,  green  lights  will  be  displaced  to 
the  right,  one  spot  for  ea<  It  />/•/>•/>/  <li<>i>t<'r.  If 
only  two  red  lights  are  seen  to  the  right  of  the 
green,  patient  has  5A  of  exophoria.  Red  line 
seen  on  a  level  with  the  first  green  spot  below 
the  center  indicates  1A  right  hyperphoria.  \Vil- 
Mains,  of  Boston,  has  improved  this  test  l»y  >uh 
stituting  luminous  figures  for  the  round  spots. 
the  arrangement  being  such  that  the  tendency 
to  "horizontalize"  or  "vci-limlhr"  is  entirely 
eliminated.  The  theoretical  superiority  of  this 
test  is  that  it  ohviates  the  necessity  of  distorting. 
blurring  or  displacing  either  retinal  image.* 

By  all   of  these   tests   <|iiite    similar    results 


*The  writer  has  fallen  into  the  habit  of  calliiii:  this  tin1 
chromatic  test.  It  mi^'lit  be  called  the  "red  and  green,"  or 
perhaps  the  Prentice  -Williams',  unless  someone  has  prior  claim. 


HETEROPHORIA    AND    HETEKOTROPIA.  17 

should  be  obtained,  but  in  one's  record  the  par- 
ticular tests  employed  should  be  indicated. 

The  cover  or  screen  test  is  quite  generally 
employed,  and  consists  in  alternately  covering 
each  eye  with  a  card,  while  the  patient  fixes  a 
distant  light.  The  eye  behind  the  card  deviates 
if  orthophoria  does  not  exist,  and  recovers  its 
fixation  when  the  other  eye  is  covered.  Prisms 
held  before  one  eye  until  all  motion  stops,  meas- 
ure the  amount  of  the  error.  This  method  the 
writer  learned  from  Suffa,  of  Boston,  in  1895. 

This  cover  test  differs  from  all  of  the  others 
in  that  it  is  a  strictly  monocular  test,  and  the 
influence  of  the  fusion  faculty  is  entirely  elimi- 
nated. It  is  argued  by  the  advocates  of  this 
method  that  it  most  truly  reveals  the  real 
tendency. 

In  cases  of  high  degree  of  heterophoria,  or 
occasional  heterotropia,  the  movement  of  each 
eye  behind  the  screen  should  be  observed- 
noting  which  recovers  its  fixation  the  more 
quickly  on  removing  the  screen.  Obviously  this 
is  the  favorite  eye,  and  the  one  that  lags  will  be 
the  one  that  is  suppressed  in  the  tests  of  fusion 
to  be  given  later. 


18  STEREOSCOPIC   TREATMENT   OF 

DUCTION. 

Whether  the  case  be  one  of  orthophoria  or 
heterophoria  it  is  important  to  know  tl it- 
strength  of  the  recti  muscles,  as  many  ortho- 
phoric  patients  have  such  weak  muscles  that 
they  are  unable  to  do  continuous  work  without 
asthenopia  or  nervous  disturbance. 

Normal  accommodation  means  that  each  eye 
shall  be  able  to  focus  an  object  as  near  as  8  to 
10  cm.  If  the  pupillary  distance  be  60  mm., 
convergence  to  this  distance  requires  60A.  If 
the  average  reading  distance  be  taken  as  30  cm., 
20A  would  be  used. 

As  the  comfortable  maintenance  of  accommo- 
dation at  30  cm.  requires  an  ability  to  accommo- 
date at  10  cm.,  so  the  convergence  faculty  must 
be  much  greater  than  the  amount  habitually 
used. 

Cross,*  of  Worcester,  Mass.,  ''believes  that 
if  the  fusion  range  is  not  at  least  twenty  per 
cent,  in  excess,  there  are  apt  to  be  more  or  less 
asthenopic  symptoms. ' ' 

Landoltf  says,  "We  have  tried  to  determine 
the  quota  of  convergence,  and  our  experience 

'Personal   communication. 

•f'Norris    and    Oliver    System    of   Eye    Diseases,"    Vol.    IV, 
p.   133. 


HETEROPHORIA   AND    HETEEOTKOPIA.  19 

seems  to  demonstrate  that  this  reserve  amount 
ought  to  be  about  twice  as  great  as  the  conver- 
gence required  by  the  work." 

Evidently  the  amount  of  reserve  convergence 
necessary  varies  with  the  hours  of  application. 
It  is  certainly  conservative  to  say  that  the  actual 
power  should  be  double  that  ordinarily  used. 

Duction  is  measured  by  the  power  to  over- 
come prisms  and  maintain  single  vision.  Loose 
prisms  from  the  trial  case  may  be  used  until  the 
limit  is  reached,  but  the  rotary  prism  is  more 
convenient. 

Howe*  has  maintained  that  the  accurate  meas- 
urement of  duction  requires  the  use  of  prisms 
in  reverse  direction,  beginning  with  one  beyond 
the  patient's  ability  to  overcome,  and  working 
down  to  weaker,  until  the  strongest  which  can 
be  fused  is  found.  This  method  was  adopted  by 
the  A.  M.  A.,  1907,  as  the  standard,  which,  it 
would  be  understood,  had  been  employed  when 
cases  were  reported  to  the  society. 

The  writer  pleads  guilty  to  having  continued 
the  old  way,  but  admits  that  repeated  trials  often 
give  quite  different  results,  showing  increasing 
power. 


"'The  Muscles  of  the  Eye." 


20  STEREOSCOPIC    TREATMENT    OF 

Although  there  is  no  general  agreement 
among  the  writers  on  this  subject,  it  is  probably 
conservative  to  consider  24A  as  normal  duction 
for  the  interni,  8A  for  the  extern!. 

CAUSES  OF   HETEROPHOHI A. 

There  are  five  generally  accepted  canst--  ..r 
heterophoria : 

First.  The  malformation  of  cranium  ami 
orbits. 

Second.  Abnormal  power,  weakness  or 
strength  of  one  or  more  muscles. 

Third.  Tendons  too  long  or  too  short. 

Fourth.  Insertions  of  tendons  too  far  t'arwanl 
or  back. 

Fifth.   Errors  of  refraction. 

But  it  is  the  author's  belief  that  a  sixth  c;m-e. 
very  generally  overlooked,  is  an  incomplete 
development  of  the  fusion  faculty.  This  <l 
not  mean  that  the  patient  possesses  no  fusion 
sense.  Fusion  faculty  is  a  question  of  decree. 
Many  true  strabismics  have  a  rudimentary 
fusion  power.  The  groat  majority  of  people  can 
fuse  large  stereoscopic  pictures,  but  many  fail 
conspicuously  when  ui\  <-n  type  of  the  size  ordi- 
narily used.  If  only  a  slight  suppression  of  one 
is  detected  during  the  test,  we  must  remember 


HETEROPHORIA    AND    HETEROTROPIA.  21 

that  tlie  very  conditions  of  the  test  force  the 
patient's  attention  to  the  separate  ob.jects  for 
the  two  eyes,  and  that  under  ordinary  conditions 
suppression  is  probably  much  more  habitual. 

It  is  also  important  to  discover  the  amplitude 
of  fusion.  Many  patients  who  possess  a  high 
degree  of  fusion  faculty  with  the  stereoscope 
adapted  exactly  to  their  normal  balance,  show 
but  little  power  to  overcome  the  slightest  ob- 
stacle. Such  cases  cannot  maintain  correct 
fusion  under  the  varying  conditions  which  the 
ordinary  use  of  the  eyes  imposes. 

SYMPTOMS  OF  HETEROPHORIA. 

Errors  of  refraction  and  heterophoria  are  so 
often  co-existent  that  it  is  difficult  to  assign  to 
each  factor  its  distinctive  symptoms. 

Not  until  the  refraction  has  been  determined 
under  a  cycloplegic  can  one  be  certain  in  any 
given  case  that  symptoms  quite  characteristic 
of  hetrophoria  are  not  produced  by  the  refrac- 
tive error.  Clinical  experience  in  relieving  a 
certain  train  of  symptoms,  which  have  persisted 
after  correction  of  refraction,  by  treating  the 
heterophoria,  is  the  basis  for  the  opinion  here 
expressed. 

In  the  order  of  importance  the  author  would 
arrange  the  symptoms  as  follows : 


22  STEREOSCOPIC   TREATMENT   OF 

Confusion. — No  localized  head  pain,  or  pain 
may  be  referred  to  the  suboccipital  region  or 
upper  part  of  back.  To  the  question,  "In  what 
part  of  the  head  is  the  disturbance!"  the  reply, 
"Oh,  I  don't  know,  all  over,"  is  so  frequent  that 
it  is  well  nigh  pathognomonic.  Inability  to  fix 
one's  mind  on  study  or  reading  is  a  frequent 
complaint. 

Difficult  Fixation.— If  esophoria,  of  a  distant 
object  like  a  public  speaker.  If  exophoria,  an- 
noyance in  conversation  in  trying  to  "look  one 
in  the  eye." 

Vertigo.— Of  mild  type,  probably  better  ex- 
pressed by  the  word  confusion. 

Drowsiness— after  reading  but  a  short  time. 

General  Nervous  Disturbance.— This  is  a  very 
large  and  somewhat  dangerous  subject,  but  it  is 
certainly  conservative  to  say  that  heterophoria 
is  frequently  a  factor  in  migraine,  "nervous 
dyspepsia"  and  epilepsey.  How  small  an  error 
may  give  rise  to  symptoms  is  a  matter  of  idio- 
syncrasy. The  same  may  be  said  of  refractive 
errors. 

For  a  further  discussion  of  this  subject,  the 
reader  is  referred  to  Stevens,  "Functional 
Nervous  Diseases"  (1884);  Howe,  "The  Mus- 
cles of  the  Eye"  (1907). 


HETEROPHORIA    AND    HETEROTROPIA.  23 

CHAPTER  III. 

TREATMENT      OF      HETEROPHORIA.   --   PRISMATIC 
GLASSES.  —  OPERATIVE.  —  MUSCLE  TRAINING.  - 
FUSION  AND  MUSCLE  TRAINING. — PHORO-OPTO- 
METER  STEREOSCOPE. 

TREATMENT  OF  HETEROPHORIA. 

Ordinarily  the  time  for  treatment  is  not  until 
after  the  correction  of  the  refractive  error,  as 
this  alone  may  suffice  to  cure  the  heterophoria, 
and,  as  a  general  rule,  with  patients  under 
thirty-five,  not  until  the  use  of  a  cycloplegic 
has  excluded  latent  refractive  error.  If  the 
refractive  error  be  slight  as  compared  with  the 
heterophoria,  one  is  justified  in  treating  the 
heterophoria  and  ignoring  the  refractive  error. 
If  the  treatment  be  by  other  means  than  the 
wearing  of  prisms,  the  patient  is  naturally  quite 
pleased  to  be  relieved  without  being  condemned 
to  wearing  glasses. 

METHODS   OF   TREATMENT. 

First.— The  wearing  of  prismatic  glasses, 
simple  or  combined  with  the  refractive  correc- 
tion, the  prisms  so  placed  as  to  correct  all  or 
part  of  the  heterophoria.  This  is  often  quite 


24  STEREOSCOPIC    TREATMENT    OF 

satisfactory  in  the  low  degrees  and  may  even 
reduce  the  error,  but  it  usually  has  the  opposite 
effect. 

This  increase  is  believed  by  many  to  be  the 
simple  uncovering  of  a  latent  tendency.  In 
esophoria  the  liability  to  increase  is  greater,  so 
that  one  may  regret  the  procedure. 

The  use  of  prisms  in  the  reverse  position,  to 
stimulate  the  defective  muscle,  has  been  advo- 
cated by  some.  The  author's  few  attempts  to 
follow  this  suggestion  have  not  been  sufficiently 
promising  to  warrant  continuance. 

Second. — Tenotomies  and  Advancements. 

In  the  higher  degrees  (more  than  10A  of  exo- 
phoria  or  5A  of  esophoria)  surgical  interference 
is  justified.  For  the  indications  the  reader  is 
referred  to  the  advice  of  Jackson  in  "  \VooiTs 
System  of  Ophthalmic  Operations." 

Although  the  writer  has  a  number  of  success 
ful  tenotomies  to  his  credit,  the  result  in  esopho- 
ria and  exophoria  has,  on  the  whole,  been  un- 
satisfactory—usually  insufficient.  For  extreme 
degrees  of  exophoria  20A-25A,  advancement  of 
the  weak  muscle  gives  good  results.  (The  .-uithor 
is  strongly  in  favor  of  advancemenl  over 
tenotomy  in  nearly  all  cases  of  heterotropia.) 
Certain  it  is  that  all  surgery  should  be  deferred 


HETEROPHORIA    AND    HETEROTROPIA.  25 

until  fusion  and  muscle  training  have  been 
thoroly  tried. 

Third.— Muscle  Training. 

This  has  been  used  principally  for  exophoria. 
Gould  arms  the  patient  with  a  pair  of  prisms 
bases  out.  10 A  stronger  than  he  can  fuse.  Eyes 
are  closed,  and  on  opening  he  fixes  a  candle  held 
10  to  20  inches  away.  The  accommodation 
assists  the  convergence  and  two  lights  are  fused. 
Candle  is  carried  to  opposite  side  of  room  while 
patient  holds  images  fused.  This  process  is 
repeated  with  increased  strength  of  prisms  till 
diplopia  results. 

Payne,  of  Boston,  gives  patients  o.  u.  pr.  4A 
to  8A  base  out  in  a  spectacle  frame  for  home  use. 
Candle  is  placed  on  opposite  side  of  the  room. 
This  the  patient  fuses  counting  ten  slowly,  the 
spectacle  is  raised  and  count  is  continued  to 
twenty,  still  fixing  the  light.  Prisms  are  lowered 
and  count  continued  to  thirty,  raised  and  count 
to  forty.  This  process  is  continued  to  one  hun- 
dred and  twenty,  which  should  require  about  two 
minutes. 

Loose  Prisms.— It  has  been  a  very  common 
practice  to  supply  the  patient  with  half  a  dozen 
loose  prisms  from  3A  to  35A,  so  that  by  combina- 
tions he  can  use  an  amount  gradually  increased 


26  STEREOSCOPIC   TREATMENT   OF 

3A.    With  these  held  before  the  eyes  he  fuses  the 
two  images  of  a  candle  across  the  room. 

After  noticing  several  patients  allow  an  rye 
to  deviate  outward,  suppress  its  image,  and  then 
declare  they  saw  one,  the  writer  decided  thai 
loose  prisms  could  be  used  safely  only  under 
eyes  of  the  oculist.  If  there  were  any 
cable  way  of  utilizing  binocular  conceptions  at 
a  distance  this  objection  might  be  overrule*  1. 

FUSION  AND  MUSCLE  TRAINING. 

The  use  of  the  stereoscope  in  after  treatment 
of  cases  operated  on  for  strabismus  has  been 
advocated  by  Smith  with  his  fusion  tubes,  by 
Landolt  with  a  modified  form  of  stereoscope, 
having  an  arrangement  for  reducing  the  illumi- 
nation of  the  object  seen  with  the  fixing  eye, 
and  by  the  late  Richard  Derby,  who  devised  a 
stereoscope  with  movable  object  carriers. 

Worth  devised  the  amblyoscope,  a 'reflect ing 
stereoscope,  with  which  fusion  is  possible,  not- 
withstanding a  high  degree  of  esotropia,  as  a 
means  of  curing  this  condition  in  the  young. 

In  1896  Javal  brought  out  his  great  work 
11  Manuel  du  Strabisme."  ll«'  seems  to  have 
been  the  first  to  adapt  the  principle  of  the  stereo- 
scope to  "latent  strabismus,"  or  heterophoria, 


HETEROPHOBIA   AND   HETEKOTROPIA.  27 

and  to  him  the  writer  feels  most  indebted.  It 
was  his  stereoscope  with  five  adjustments  that 
suggested  the  utilizing  of  the  phoro-optometer 
for  the  same  purpose.  It  seems  incredible  that 
a  work  of  such  great  merit  should  not  have  ap- 
peared in  English. 

His  charts,  graded  from  easy  to  difficult, 
opened  up  an  entirely  new  and  practical  field  in 
fusion  training.  In  1904  some  of  these  were 
reproduced  in  English  in  the '"Wells  Selection 
of  Stereoscopic  Charts."  Most  of  the  other 
charts,  like  Kroll's,  Dahlf eld's  and  Hale's,  were 
adapted  to  secure  only  the  rudiments  of  binocu- 
lar vision. 

Much  good  work  can  doubtless  be  done  with 
an  ordinary  stereoscope,  but  in  order  to  carry 
out  the  author 's  methods  one  must  have  a  phoro- 
optometer,  with  two  rotary  prisms  and  the 
stereoscopic  attachment.  The  phoro-optometer 
had  been  in  constant  use  several  years  before 
its  adaptability  as  a  training  stereoscope  was 
discovered. 

The  first  apparatus  was  made  with  an  adjust- 
able focus  so  that  spheres  from  +5.00  to  +10.00 
could  be  used.  This  was  later  discarded  and  a 
permanent  distance  of  10  cm.  used.  With  this 
+10.  spheres  are  always  in  focus. 


28  STKI.'Kosroi'ir    TREATMENT    <>1 

Following  the  model  of  the  late  Dr.  Richard 
Derby,  adjustable  object  carriers  were  provided, 
'with  somewhat  elaborate  mechanism  for  verti- 
cal adjustment  and  an  endless  screw  for  ap- 
proximating and  separating  them.  This  was 
essential  to  secure  a  gradual  and  smooth  mo\< 
ment,  otherwise  the  eyes  ceased  to  follow  and 
fuse  the  two  objects. 


KM;.  ('..     PHOBO-OTTOMKTEB  S  i'i . 

After  using  this  arrangement  SOUK-  time,  it 
was  discovered  that  patients  who  foutfd  <rreat 
difficulty  in  keeping  the  objects  fused  as  the 
carriers  were  approximated)  were  much  le>s 
disturbed  if  the  spheres  were  separated  l>\  turn- 
ing the  screw  for  pupillary  adjustment,  and  that 


HETEROPHORIA    AND    HETEROTROPIA. 


29 


a  much  greater  degree  of  prism  could  in  this 
way  be  fused. 

The  Wells  stereoscopic  attachment  to  the 
phoro-optometer  illustrated  in  ' '  Meyrowitz  Bul- 
letin," 1903,  shows  the  movable  object  carriers, 
but  in  the  author's  instrument  they  soon  became 
fixed  at  6  cm.  apart. 

It  was  later  discovered  that  if  one  were  a  little 


FIG.  7. — NEW  PHORO-OPTOMETER  STEREOSCOPE  SHOWING 
SIMPLE  CLIP  TO  HOLD  CARDS. 


30  STEREOSCOPIC    TREATMENT    OF 

careless  in  fixing  the  objects  in  the  carriers,  a 
slight  tilting  or  vertical  error  interfered  with 
fusing,  so  the  object  carriers  fell  into  disuse  and 
stereoscopic  cards  were  used  instead.  The  im- 
proved form  is,  therefore,  simply  the  addition 
to  the  phoro-optometer  of  a  clip  to  hold  the 
cards. 

In  1904  the  Wells  selection  of  stereoscopic 
cards  was  published.  This  was  a  selection  of 
the  most  useful  from  those  previously  brought 
out  by  Kroll,  Dahlfeld,  Hale  and  Javal.  Only 
a  few  new  cards  were  added  by  the  writer. 

A  second  edition  has  now  become  necessary. 
The  new  edition  includes  some  very  ingenious 
tests  in  fusing  complementary  colors  by  Dr. 
George  A.  Shepard,  of  New  York,  and  a  new  set 
for  amplitude  training  by  the  author.  The 
lettering  and  grading  have  been  somewhat 
changed. 

To  guard  against  any  misunderstanding  the 
reader  should  bear  in  mind  that  in  the  instruc- 
tions which  follow,  the  letters  and  figures  refer 
to  the  second  edition,  which  is  being  published 
at  the  same  time  with  this  book. 

DECENTERING  SPHERES  TO  SECURE  PRISM. 

The  application  of  the  principle  of  decenter- 
ing  of  the  spheres  for  the  purpose  of  introduc- 


HETEROPHORIA    AND    HETEROTROPIA.  31 

ing  extra  prismatic  effect,  as  applied  to  fusion 
training,  is  believed  to  be  original  with  Javal,* 
but  it  has  been  greatly  extended  by  the  author, 
and  its  superiority  over  any  other  method 
known  to  him  justifies  a  somewhat  detailed  de- 
scription. 

With  o.  u.  +10.,  cards  at  10  cm.  are  in  focus. 
If  the  separation  corresponds  to  that  of  the 
pupillary  distance  of  the  patient's  eyes,  no  pris- 
matic element  is  exhibited.  If  decentered  1 
mm.,  1A  approximately  is  produced.  Thus  +10. 
spheres  make  the  calculation  of  the  prism  ex- 
tremely simple.  If  the  spheres  are  decentered 
out  5  mm.,  we  have  put  before  the  patient  5A  of 
prism  base  out,  just  as  truly  as  tho  a  5A 
prism  were  inserted  in  the  clip.  If  the  spheres 
are  decentered  in  5  mm.,  5A  base  in  is  obtained. 
As  the  pupillary  adjustment  may  be  varied  from 
50  to  75  mm.,  it  follows  that  10A  or  more  may  be 
utilized  by  this  simple  principle  of  decentration. 

*"Manuel  du  Strabisme,"  p.  115. 


32  STEREOSCOPIC    TREATMENT   OP 


CHAPTER  IV. 

STEREOSCOPIC  TREATMENT  OF  EXOPHORIA.— AU- 
THOR *S  CARD  FOR  MEASUREMENT  OF  STEREO- 
SCOPIC HETEROPHORIA. — AMPLITUDE  OF  FU- 
SION.—RECOVERY  EXERCISES.  — HOME  IXI.K 
CISES. — THE  SUPPRESSED  EYE. — CONTROLLED 
READING. — AUTHOR'S  DEVICE. — NUMBER  OF 
CASES  TREATED  AND  RESULTS. 

STEREOSCOPIC  TREATMENT  OF  EXOPHORIA. 

Let  us  suppose  a  case  of  exophoria  of  10A  dis- 
tance, adduction  subnormal,  greater  conver- 
gence faculty  needed.  With  o.  u.  +10.  in  the 
clips,  centered  to  correspond  to  patient's  pupil- 
lary distance,  card  marked  BI  is  put  in  clip,  and 


876543 

FIG.  8.— BL 

the  patient  is  asked  over  which  dot  he  sees  the 
arrow.  He  will  probably  answer  "five"  or 
"between  five  and  six."  If  five,  this  means  that 
he  has  selected  the  number  five  spot  with  which 


HETEROPHORTA   AND    HETEROTROPIA. 


33 


FIG.  9. — SHOWING  THE  LINES  OF    SIGHT  WHEN   THE  PATIENT 
SEES  THE  ARROW  OVEB  5'. 


34  STEREOSCOPIC    TREATMENT    OF 

to  fuse  the  arrow  spot,  therefore  5  cm.  is  the 
patient's  easiest  fusion  distance  with  o.  u.  +10. 
Glasses  correcting  the  refractive  error  should, 
of  course,  be  worn  and  if  there  is  much  pres- 
byopia, the  o.  u.  +  10.  should  be  made  enouirh 
stronger  to  correct  it.  This  will  slightly  increase 
the  prismatic  effect  of  the  decentering. 

Eyes  are  closed  and  the  two  rotary  prisms 
swung  into  position  to  give  o.  u.  5A  base  out. 
Patient  opens  his  eyes  and  again  states  position 
of  arrow.  If  over  six  the  amount  of  prism  which 
makes  six  centimeters  the  easiest  fusion  distance 
has  been  found.  If  not  correct  one  or  two  trials 
will  secure  it.  Should  arrow  be  seen  between  six 
and  seven,  less  than  o.  u.  5A  is  required ;  should 
it  be  seen  between  five  and  six,  more  than  o.  u. 
5A  is  needed. 

As  all  the  cards,  except  series  H.  B  and  T,  are 
6  cm.  between  centers,  the  stereoscope  is  now 
approximately  suited  to  this  particular  patient, 
and  we,  therefore,  proceed  to  test  his  fusion 
faculty.  Unless  the  case  be  one  of  anisome- 
tropia  or  amblyopia,  it  is  well  to  begin  with 
series  F. 

Patient  should  see  the  vertical  lino  passing 
through  the  dot.  If  the  line,  which  is  seen  by 
the  left  eye,  is  too  far  to  the  right;  that  is, 


HETEROPHORIA   AND    HETEROTROPIA.  35 

heteronomous  diplopia,  the  prism  base  out 
should  be  reduced  till  the  direct  alignment  is 
secured.  If  the  line  be  to  the  left  of  the  dot,  it 
is  evident  that  the  reverse  is  indicated. 


Fi 

g 
o 

o 

d 

(Javal  KI3) 

By  means  of  the  card  Bs  the  exact  prism 
needed  may  be  determined.  Obviously  it  is  the 
amount  with  which  the  patient  sees  the  lines 
intersect  at  six,  but  the  cruder  method  with  Bx 
is  preferable  in  the  beginning. 

B3  is  designed  especially  for  the  accurate 
measurement  of  stereoscopic  hyperphoria, 
which  is  often  quite  different  from  that  shown 
by  other  tests.  The  divisions  of  the  red  vertical 
line  are  5  mm.  apart.  If  the  black  horizontal 
line  is  seen  to  cross  the  red  vertical  line  at 
H,  5A  right  hyperphoria  is  exhibited.  Hyper- 


36 


STEREOSCOPIC   TREATMENT   OF 


phoria  may  interfere  with  fusion.  It  is  then 
necessary  to  correct  all  or  part  of  it  with  a 
vertical  prism  in  the  clip. 


BJ 


IWellj) 


Fic.  11. 

Patient's  eyes  are  closed  (unless  other \\  i si- 
stated,  it  is  to  be  assumed  that  patient's  eyes  are 
always  closed  before  each  change)  and  sue 
ceeding  numbers  of  F  used  in  numerical  order. 
It  should  be  noted  if  either  eye  fails  to  see  its 
respective  lines  and  dots,  and  if  suppression 
occur,  whether  it  be  always  *of  the  same  eye  or 
of  alternate,  right  and  left.  Let  us  suppose 
that,  beginning  with  F4,  the  left  eye  fails  to 
the  line  or  dots  belonging  to  the  left  picture, 
altho  the  letters  are  correctly  read. 

The  case  should  be  recorded : 

"Stereoscope  +  10.  =  5  cm.,  o  Pr.  o.  u.  5A  B 
out  =  6  cm.    Suppresses  Left  F4,  5,  e,  7,  s." 


HETEROPHOEIA   AND    HETEROTROPIA.  37 

This  test  might  have  been  made  with  Cg  or 
series  G,  but  it  has  been  found  that  series  F  fur- 
nishes quicker  and  more  reliable  information. 

Series  E  is  devoted  to  perspective. 

If  with  Ei,  the  antero-posterior  relation  of 
the  dots  is  correctly  stated,  the  subsequent 
numbers  are  tried  in  order.  If  Es  is  not  cor- 
rectly seen,  to  the  record  is  added  "E,  o.  K.  to 
4"or"FailsE5." 

AMPLITUDE  OF  FUSION. 

CT  is  now  put  in  place,  and  as  the  N  's  are  just 
six  centimeters  between  centers,  the  two  N's  are 
perfectly  fused  and  the  patient  reads  "  ONE." 


ON      NE 


(Wells) 


FIG.   12.— C7. 


Now  while  the  patient  watches  the  fused  im- 
age, the  P.  D.  of  the  spheres  is  increased  by 
gradually  turning  the  screw  to  the  limit  (75  mm. 


38  STEREOSCOPIC    TREATMENT    OF 

P.  D.).  Eyes  are  then  closed  and  P.  D.  of 
spheres  is  reduced  to  minimum  (55  mm.).  5A 
more,  making  20A  in  all,  is  now  turned  up  in 
each  prism.  Patient  will  fuse  this  easily— but 
let  us  note  just  what  has  been  accomplished. 

Assume  P.  D.  =  60  mm.,  then  he  has  fused 
20A  less  5A  =  15A.  As  10A  was  required  to  brinir 
the  arrow  over  six  on  the  BI  card,  15A  less  10A= 
5A  =  effort  put  forth.  This  process  is  repent* •«!. 
adding  from  5A  to  10A  each  time  till  the  ",ONE" 
breaks  apart  before  the  spheres  are  fully  sepa- 
rated.  If  this  occur,  using  o.  u.  Pr.  25A.  wlien 
spheres  show  65A  P.  D.,  record  should  road. 
"amplitude  'ONE'  or  C7  55V 

Much  can  be  learned  by  watching  the  patient'- 
eyes  over  the  top  of  the  plioro-optometer. 
Usually  they  both  converge  equally,  but  o< 
sionally  one  eye  will  participate  but  little.  ;ni<l 
this  will  be  the  eye  which  is  suppressed  in  the 
finer  tests  of  fusion  faculty.  The  treatment  of 
this  condition  will  be  taken  up  later,  but  it  is 
here  noted  to  emphasize  the  importance  of 
observing  all  the  conditions. 

Tn  this  particular,  this  form  of  stereoscope 
overcomes  a  serious  objection  to  the  amblyo- 
scope,  because  with  the  latter,  the  eyes  cannot 
be  watched,  and  \ve  must  depend  on  the  patient 's 


HETEROPHOBIA    AND    HETEKOTKOPIA.  39 

statements,  which  are  naturally  very  unreliable, 
especially  when  treating  children. 

But  to  return  to  our  case : 

The  limit  of  fusion  would  be  perhaps  40A-  50A 
on  this  first  trial.  Phoro-optometer  is  then  re- 
moved and  loose  prisms  held  before  the  eyes 
base  out,  and  strength  increased  until  the  limit 
for  fusing  a  distant  light  is  reached. 

Pneumo  massage  or  fine  Faradic  electricity 
is  given.  The  pneumo  massage  is  more  agree- 
able to  the  patient.  It  may  be  that  this  has  no 
further  importance  than  the  soothing  and  sug- 
gestive effect. 

This  whole  treatment  requires  15  to  25  min- 
utes, and  is  given  three  times  a  week  for  three 
weeks,  or  until  sufficient  power  has  been  at- 
tained. After  the  60A  of  the  two  rotary  prisms 
has  been  fused,  round  prisms  from  trial  case 
are  inserted  in  the  clips.  It  is  practicable  to 
use  as  high  as  10A  before  the  right  eye  and  20A 
before  the  left,  This  furnishes  90A  in  all  with- 
out any  decentering.  Just  what  constitutes  suffi- 
cient power  is  not  a  fixed  amount  for  all  cases. 
Successful  ones  average  80A  to  90A  with  the 
phoro-optometer  stereoscope,  and  50A-60A  loose 
prisms.  Many,  especially  the  younger,  will  de- 
velop an  amplitude  of  over  100A,  both  with 


40 


STEREOSCOPIC    TREATMENT    OF 


stereoscope  and  loose  prisms.  When  sufficient 
power  has  been  gained,  time  between  treatments 
is  gradually  lengthened  to  two  a  week,  one  a 
week,  one  in  two  weeks,  etc.,  provided  the  maxi- 
mum reached  at  previous  visit  is  still  attainable. 


Kit,. 

It  may  be  well  to  try  the  holding  power  of 
other  cards,  especially  the  L,  F,  the  fusion  of 
which  makes  E,  but  it  is  believed  that  the  OXK 
gives  the  greatest  mental  stimulus,  as  one's 
sense  of  proportion  is  disturbed  at  seeing  the 
letters  break  apart. 

RECOVERY  EXERCISES. 

The  treatment  is  sometimes  varied  by  what 
the  writer  calls  the  recovery  exercise.   AVitb  ('- 
a  few  trials  at  decentering  are  made,  the  e; 
allowed  to  close  when  the  fusion  limit  is  reached, 


HETEROPHOETA   AND    HETEROTROPIA.  41 

and  then  the  patient  is  told  that  this  time  his 
eyes  are  to  remain  open,  that  he  must  speak  the 
instant  he  feels  that  he  is  about  to  lose  his  fused 
image,  and  that  the  prisms  will  be  turned  to  help 
him  get  it  clear  again.  It  requires  several  trials 
before  he  can  overcome  the  tendency  to  close  the 
eyes,  and  then  the  prisms  will  need  to  be  reduced 
very  much  before  he  will  say  "all  right,  I  have 
it  now. ' ' 

After  six  or  eight  trials  the  recovery  will  be 
very  much  quicker  and  will  require  only  a  slight 
reduction  of  prism.  It  is  believed  that  this 
exercise  has  considerable  practical  value  in 
teaching  the  patient  to  overcome  the  slight  turn- 
ing tendencies,  which  may  annoy  him  in  reading. 

HOME  EXERCISES. 

The  patient  is  required  to  buy  a  Holmes' 
stereoscope  with  clips  for  inserting  extra 
prisms,  and  a  set  of  the  "Wells'  stereoscopic 
charts.  It  is  important  that  the  patient  own 
these,  as  he  is  expected  to  use  them  occasionally 
for  some  months,  to  insure  his  retaining  his 
newly  acquired  faculty.  These  charts  are  not  to 
be  used  indiscriminately,  but  in  accordance  with 
very  6xact  instructions. 

If  at  first  examination  the  case  showed  a  fair 


42  STEREOSCOPIC   TREATMENT    OF 

degree  of  fusion  faculty,  seeing  half  the  cards 
in  series  F,  G  and  E,  he  is  given  F  and  G  to 
use  in  numerical  order,  stopping  when  a  few 
seconds  fail  to  secure  perfect  fusion  of  the  let- 
ters. This  exercise  requires  ten  to  fifteen  min- 
utes and  should  be  done  three  times  a  day. 


FIG.  14. — HOLMES'  STEREOSCOPE  WITH  CLIPS  FOB  KXTUA  I'UISMS. 


After  second  visit,  series  E  may  be  added 
to  homework  with  instructions  to  run  rapidly 
through  F  and  G.  When  these  cards,  which  are 
6  cm.  between  centers,  are  mastered  fairly  (not 
necessarily  perfectly),  series  II  and  I  are  to  be 
used  in  the  following  manner:  Patient  inserts 
Bi,  notes  position  of  arrow  and  selects  the  same 


HETEROPHOBIA   AND    HETEROTROPIA.  43 

number  of  series  H  or  I  to  begin  with.  For 
example,  if  with  BI  arrow  is  seen  over  six,  He 
is  the  first  to  be  used.  This  will  be  fused  with 
ease,  as  it  is  the  distance  between  centers  to 
which  patient  and  stereoscope  are  adjusted.  The 
order  is  now  toward  the  smaller  number,  5} £,  5, 
44/2,  etc.,  as  it  is  convergence  amplitude  which 
is  needed.  When  the  narrowest  of  these  cards 
can  be  easily  fused,  a  pair  of  5A  prisms  is  in- 
serted in  the  clips,  bases  out,  and  the  same  exer- 
cise repeated.  In  exceptional  cases  a  pair  of 
10A  prisms  is  used. 

In  the  average  case  ten  to  twelve  treatments 
suffice^ to  put  the  patient  on  an  independent 
basis;  that  is,  he  has  learned  the  knack,  appre- 
ciates the  relief  of  perfect  fusion,  and  knows 
how  to  send  the  required  neuricity  to  the  inter- 
nal recti. 

For  further  refinement  of  fusion,  Dr.  George 
A.  Shepard,  of  New  York,  has  devised  some 
very  ingenious  exercises  in  fusing  colors.  His 
instructions  are  as  follows : 

' '  Series  D  is  designed  to  be  used  in  those  cases 
in  which  the  muscular  power  is  good,  but  the 
patient's  ability  to  blend  the  images  of  the  two 
eyes  into  a  satisfactory  binocular  impression  is 
deficient. 


44  STEREOSCOPIC   TREATMENT   OF 

"As  the  fusion  function  consists  of  a  subcon- 
scious control  of  the  visual  lines,  it  is  essential 
that  the  activity  of  the  psychic  center  be  strongly 
stimulated.  In  order  to  do  this,  cases  must  be 
individualized  and  such  cards  be  presented  as 
will  best  catch  the  attention  and  tickle  the  imagi- 
nation. While  it  is  still  a  moot  point  as  to 
whether  the  perception  of  color  is  to  be  placed 
in  the  sphere  of  physiology  or  psychology,  there 
can  be  no  question  that  the  blending  of  two 
monocular  complementary  colors  into  a  neutral 
tint  must  be  purely  psychic.  Where  objects  of 
the  same  form  are  to  be  fused,  or  where  the 
separate  images  are  incomplete,  a  desire  for 
symmetry  in  the  one  and  a  striving  to  satisfy 
a  memory  picture  in  the  other  serve  as  strong 
incentives  to  fusion.  Hence,  it  is  necessary,  in 
a  certain  proportion  of  cases,  to  eliminate  these 
factors  if  perfect  self-reliance  is  to  be  estab- 
lished. 

1 1  The  D  series  has  retained  the  same  form  and 
size  of  figure  for  the  two  eyes  to  aid  the  patient 
in  properly  adjusting  the  visual  lines  so  the 
colored  rectangles  shall  fall  upon  the  corre- 
sponding retinal  areas,  but  the  neutralization  of 
the  colors  demands  that  proper  values  be  given 
to  each  impression.  This  series  cannot  be  used 


HETEEOPHOEIA   AND    HETEROTKOPIA. 


45 


to  advantage  if  the  patient  has  congenitally  de- 
fective color  sense  or  is  suffering  from  noncon- 
centric  contraction  of  the  color  field,  such  as 
often  occurs  in  neurasthenia. 

' '  The  exercise  can  be  made  still  more  exacting 
by  having  the  form  of  the  colors  dissimilar  and 
eliminating  the  control  gray  tint/ but  this  would 
require  the  constant  personal  attention  of  the 


FIG.  15. — SHOWING  DOTS  MASKED  ON  STEREOGRAPH. 

observer  and  make  the  charts  less  useful  for 
homework. ' ' 

Many  years  ago  Landolt  suggested  the  use  of 
the  ordinary  stereoscopic  pictures,  putting  two 
dots  on  one  picture  and  a  third  dot  on  the  other, 
so  that  the  three  will  appear  in  a  vertical  line  in 
the  fused  image. 


46 


STEREOSCOPIC   TREATMENT   OF 


For  homework  after  the  patient  has  ceased 
his  regular  visits,  two  or  three  dozen  of  such 
photos,  selected  by  him,  are  marked  in  this  way, 
the  dots  being  made  as  small  as  possible..  He  is 
thus  taught  to  appreciate  the  absolute  reproduc- 


FIG.  16. — DB.  CROSS'  STEREOSCOPIC  ATTACHMENT  FOR  H<>MI 
EXERCISING. 

tion  of  natural  scenery,  and  is  constantly  able  to 
verify  his  binocular  perception  by  a  glance  at 
the  dots. 

It  is  advisable  to  insist  upon  good  photo- 
graphs properly  mounted.  The  H.  C.  White 
Company,  of  Bennington,  Vt.,  offer  a  fine  selec- 
tion of  views  from  all  parts  of  the  world. 


HETEROPHORIA   AND    HETEROTROPIA.  47 

Cross,  of  Worcester,  Mass.,  has  devised  a 
cylinder  with  13  facets,  on  which  he  has  pasted 
the  13  cards  of  series  H.  This  is  mounted  on  the 
Holmes  stereoscope,  arranged  with  a  ratchet  so 
that  the  patient  can  turn  up  one  after  the  other 
of  the  cards,  progressing  in  either  direction.  If, 
as  some  think,  it  is  wiser  to  have  a  period  of 
relaxation  between  the  repeated  efforts  of  con- 
vergence, Cross  suggests  that  patient's  eyes  may 
be  closed  while  the  cylinder  is  being  revolved. 

CONTROLLED  READING. 

Javal  illustrates  the  control  device  of  Bull, 
which  is  an  aff air  somewhat  resembling  a  stereo- 
scope with  an  opaque  bar  midway  between  the 
eyes  and  a  card  placed  in  the  clips.  To  over- 
come the  possibility  of  a  patient  reading  alter- 
nately with  right  and  left,  Javal  constructed  his 
"grill,"  a  little  table  with  five  vertical  bars. 
This  is  placed,  standing  on  four  legs,  on  the  page 
to  be  read. 

After  experimenting  with  various  appliances 
the  author  devised  a  control  which  enables  the 
principle  to  be  applied  to  all  of  the  patient's 
reading,  writing  and  sewing.  A  description  and 
illustration  of  this  was  published  in  Meyrowitz 
Bulletin,  January,  1905. 


48 


STEREOSCOPIC    TREATMENT    OF 


It  consists  of  an  ordinary  head  band,  either 
leather,  silk  or  the  metal  spring,  but  in  place 
of  the  mirror,  an  aluminum  band  is  attached  by 
the  ball  and  socket  joint.  This  admits  of  con- 


FIG.   17. — AUTHOR'S  CONTROL  DKVICE. 


siderable  adjustment,  which  can  be  supple- 
mented by  bending  the  aluminum.  The  band  is 
blackened  to  avoid  reflections,  and  is  placed  half 
way  between  the  face  and  the  page.  If  either 
eye  be  suppressed  a  black  band  is  seen  across 


HETEEOPHOEIA    AND    HETEROTROPIA.  49 

the  page.  This  is  shown  to  the  patient  by  alter- 
nately covering  the  eyes.  If  patient  does  not 
occupy  a  conspicuous  place,  this  control  can  be 


FIG.   18. — TBIPLE  CONTROL  DEVICE. 


used  for  practically  all  near  work,  and  this  is 
insisted  upon.  At  first  there  will  be  some  com- 
plaint, but  most  patients  soon  come  to  appreciate 


50  STEREOSCOPIC    TREATMENT   OF 

the  steadying  effect  and  the  ability  to  read  with 
more  comfort. 

The  latest  model,  Fig.  18,  has  three  control 
bands  and  resembles  an  inverted  trident.  The 
central  band  is  10  mm.  wide,  the  lateral  ones  7. 
and  the  spaces  13  mm.  If  this  be  held  not  more 
than  15  cm.  in  front  of  the  eyes,  the  field  >  ovei 
lap  sufficiently  to  allow  of  comfortable  reading, 
but  three  times  in  each  line  the  control  principle- 
is  brought  into  play. 

With  a  pupillary  distance  of  60  mm.,  the  con- 
trol at  15  cm.  and  the  reading  held  at  '.'>~>  cm. 
(14  inches),  the  overlapping  is  about  6  mm. 
Obviously  this  increases  with  the  distance. 

This  triple  control  necessitates  more  exact 
adjustment  than  the  single  band,  and  may  not 
be  practicable  for  all  near  uses,  but  for  quiet 
reading,  it  prevents  suppression  as  effectually 
as  JavaPs  "grill." 

The  author  is  familiar  with  Gould's  theory  of 
dextro  and  sinistro-ocularity,*  but  feds  ohli.uv.l 
to  differ  from  the  opinion  that  any  marked  sup 
pression  of  either  eye   is    physiological.     l"n- 
doubtedly  many  people  who  habitually  suppress 

'Ophthalmology,  Oct.,  1904 


HETEROPHOEIA   AND    HETEROTROPIA.  51 

one  eye  may  not  suffer  any  annoyance  from  this 
condition.  The  same  may  be  said  of  errors  of 
refraction,  but  does  anyone  for  that  reason  con- 
sider astigmia  physiological!  The  writer  main- 
tains that  the  habitual  use  of  the  two  eyes 
binocularly,  with  a  minimum  of  suppression  of 
either,  is  as  ideal  as  is  the  emmetropic  eye  to 
uniocular  vision. 

Therefore,  every  known  means  is  utilized  to 
overcome  this  suppression.  If  marked,  it  is  ad- 
missible to  atropinize  the  favorite  eye.  One  of 
the  less  powerful  cycloplegics  is  generally  suffi- 
cient. A  thin  film  of  soap  may  be  smeared 
on  the  stereoscopic  lens  corresponding  to  the 
favorite  eye.  The  whole  object  is  to  force  the 
patient's  use  of  the  suppressed  eye,  by  handi- 
capping the  favorite  one. 

NUMBER  OF  CASES  TREATED  AND  RESULTS. 

In  advocating  a  new  method  of  treatment,  it 
is  realized  that  something  must  be  said  about 
results,  but  it  is  a  somewhat  difficult  task  to 
report  accurately  concerning  therapeutic  ac- 
complishments. 

Probably  nine-tenths  of  those  treated  have 


52  STEREOSCOPIC   TREATMENT    OF 

been  exophorics,  so  that  of  this  class  there  have 
been  a  sufficient  number  to  justify  one  in  draw- 
ing some  conclusions.  Tn  the  last  five  years 
330  cases  of  this  class  have  been  treated  by  tlio 
methods  explained  above.  Of  these  about  sixty 
per  cent,  have  gained  a  good  convergence 
faculty  varying  from  60A  to  90A,  and  the  symp- 
toms have  been  relieved.  Some  of  these  have 
become  orthophoric  by  the  various  phorometer 
tests.  Others  still  exhibit  some  exoplioria,  Imt 
much  less  than  before.  These  are  all  classed  as 
" cured."  Fifteen  per  cent,  have  developed 
equally  good  convergence,  but  symptoms  are  not 
relieved.  Evidently  symptoms  were  not  caused 
by  insufficiency.  Fifteen  per  cent,  more  have 
attained  to  30A  or  40A  and  secured  partial  relief. 

About  ten  per  cent,  must  ln»  Classed  as  fail- 
ures. No  improvement  in  muscle  power  could 
be  secured.  For  some  reason  they  did  not 
respond.  These  last  were  not  given  a  full  course 
of  treatment.  If  marked  improvement  is. not  evi- 
dent after  five  or  six  visits,  the  treatment  is 
stopped. 

Undoubtedly  this  list  includes  some  cases  of 
nervous  instability,  which  a  keener  diagnosti- 
cian would  have  referred  to  the  neurologist. 
There  have  been  some  relapses,  but  the  great 


HETEROPHORIA   AND    HETEROTROPIA.  53 

majority  of  the  "cured"  cases  have  retained 
sufficient  power  for  all  practical  purposes.  Pa- 
tients are  admonisjied  to  test  themselves  from 
time  to  time  with  the  stereoscope  and  cards,  and 
if  they  notice  any  loss  of  power,  to  renew  the 
home  exercises. 


54  SI  KIM.OSCOPIC    TREATMENT    Ob" 


CHAPTER  V. 

STEREOSCOPIC  TREATMENT  OF   ESni'll' HMA.  — MA"\ 

AN      EXPRESSION      OF      CONYKKi  ii.N  <  I.      INSl'lll 
CIENCY.  —  FUSION  TRAINING  SAME  AS  FOR   1 
PHORIA.  — AMPLITUDE    TRAINING    Till.    IIKVI 
OR  MAY  BE  THE  SAME  AS  FOR  EXOPHORIA. 

ESOPHORIA. 

The  proper  treatment  of  esophoria  nee 
tates  a  proper  estimation  of  all  the  factors  con- 
cerned.    One  is  not  justified  in  concluding  that 
the   convergence  faculty  is  too  strong.      1 
phoria  at  distance  is  often  associated  with  exo- 
phoria  at  near.    In  these  cases  duction  will  be 
found  quite  limited. 

Paradoxical  as  it  may  seem,  the  writiT  is 
convinced  that  esophoria  at  a  distance  is  not 
infrequently  an  expression  of  convergence 
insufficiency.  Just  how  this  is  brought  about  he 
has  no  very  definite  opinion,  but  as  the  conver- 
gence function  is  the  one  most  directly  under 
the  control  of  the  will,  it  is  conceivable  that  it 
might  be  exercised  "not  wisely,  but  too  well" 
in  a  vain  effort  to  overcome  some  annoying 
exophoria  or  hyperphoria. 


HETEROPHORIA    AND    HETEROTROPIA.  55 

Esophoria,  dependent  on  latent  hyperopia,  is 
quite  common,  and  there  is  a  consensus  of  opin- 
ion as  to  what  this  association  implies.  The 
constant  need  of  innervation  of  the  ciliary  for 
distance,  as  well  as  near,  in  some  way  causes 
an  overstimulus  of  the  associated  convergence— 
the  coordination  is  disturbed.  The  full  cor- 
rection of  the  whole  refractive  error  under 
atropine  is,  therefore,  the  first  requirement  and 
usually  gives  relief,  but  many  of  these  cases 
show  no  reduction  of  the  esophoria,  the  symp- 
toms persist  and  the  blurring  of  distant  objects 
is  quite  annoying.  For  these  cases  and  those 
not  hyperopic,  what  shall  be  done?  The  use  of 
prisms  base  out  frequently  "begets  the  calami- 
tous necessity  of  keeping  on."  With  each 
increase  of  prism  more  esophoria  develops,  till 
one  may  be  forced  to  do  a  tenotomy  or  advance- 
ment to  give  his  patient  relief. 

The  stereoscopic  treatment  consists  first  of  a 
thorough  testing  of  the  fusion  faculty,  and  if 
any  defect  be  found,  the  use  of  controlled  read- 
ing (explained  in  Ghap.  IV)  and  the  stereo- 
scopic charts  which  cultivate  a  refinement  of 
fusion,  like  D,  E,  F,  G.  To  this  point  the  treat- 
ment may  be  identical  with  that  given  for 
exophoria. 


56  STEREOSCOPIC   TREATMENT   OP 

In  using  the  phoro-optometer  stereoscope, 
patient  should  learn  to  fuse  with  prism  base  in, 
if  we  are  to  secure  a  greater  divergence  power. 
The  same  o.  u.  +10.  are  used  in  the  frame,  and 
card  Bi  determines  the  easiest  fusion  distance 
by  position  of  arrow.  Let  us  suppose  it  be  seen 
over  three,  this  means  that  the  two  discs  3  cm. 
apart  are  the  easiest  fusion  distance. 

Rotary  prisms  15A  each  base  out  ought  theo- 
retically to  bring  the  arrow  over  6.  C?  ON  NE 
is  then  introduced  and  the  spheres  approxi- 
mated so  as  to  reduce  the  base  out  of  the  rotary 
prisms.  When  limit  has  been  reached,  patient's 
eyes  are  closed  and  the  lenses  separated  as  far 
as  possible,  and  the  base  out  of  the  rotaries 
reduced  5A,  leaving  10 A  each. 

If  the  patient's  pupillary  distance  be  60  mm. 
and  the  phoro-optometer  show  70  mm.  P.  D., 
15A  each  base  out  will  be  exhibited  in  this  wide 
open  position  and  this  will  be  as  easily  fused  as 
at  first.  Now  if  the  spheres  be  approximated 
while  the  patient  holds  the  letters  fused,  when 
P.  D.  60  has  been  reached,  the  prismatic  element 
of  the  decentering  has  been  eliminated,  and  the 
amount  as  shown  by  the  revolving  prisms,  10A 
each,  is  the  total.  If  the  approximation  be  con- 
tinued to  50  P.  D.,  then  the  5A  each  base  in 


HETEEOPHOEIA   AND    HETEROTROPIA.  57 

produced  by  the  decentering  reduces  the  base 
out  of  the  revolving  prisms,  and  the  patient  has 
diverged  from  his  first  position  and  maintained 
fusion  with  o.  u.  5A  base  out. 

Eyes  are  now  closed  again  and  the  spheres 
separated  as  far  as  possible.  Rotary  prisms  are 
now  reduced  5A  each,  so  that  the  reading  which 
was  before  10^  is  now  5A.  Patient  opens  his 
eyes  and  if  he  is  able  to  fuse  the  ON  NE,  lenses 
are  approximated  as  before.  This  process  is 
repeated  with  smaller  changes  in  amount  of 
rotary  prisms  as  it  becomes  evident  that  pa- 
tient's limit  is  becoming  reached. 

As  was  said  before,  the  home  use  of  the  cards 
as  far  as  series  G  is  the  same  with  all  forms 
of  heterophoria,  because  with  all  of  these  cards 
the  distance  between  centers  is  6  cm.,  and  their 
use  is  for  the  cultivation  of  a  refinement  of  the 
fusion  faculty.  For  amplitude  training  it  is 
evident  that  the  progression  in  the  use  of  series 
H  and  series  I  must  be  reverse  of  that  for 
exophoria;  that  is,  if  patient  sees  the  arrow 
over  4  with  Bi  card,  he  should  commence  with 
m  or  14  and  work  up  to  higher  numbers,  5,  6,  7, 
etc.  In  many  cases  where  there  has  been  pres- 
ent esophoria  for  distance  and  exophoria  for 
near  the  convergence  duction  has  been  found  so 


58  STEREOSCOPIC   TREATMENT   OF 

poorly  developed  that  the  writer  has  treated 
the  case  the  same  as  for  exophoria,  both  with 
the  phoro-optometer  stereoscope  and  the  home- 
work for  cultivating  amplitude. 

Increased  convergence  has  relieved  the  symp- 
toms and  has  not  increased  the  esophoria.  In 
some  instances  orthophoria  has  been  restore* I. 
It  is  experiences  like  these  which  have  forced 
the  conclusion  that  there  exists  a  pseudo- 
esophoria,  which  should  be  interpreted  as  an 
insufficiency  of  convergence  and  not  excess. 


HETEROPHORIA    AND    HETEROTROPIA.  59 


CHAPTER  VI. 

TREATMENT  OF  H YPERPHORIA.  —  STEREOSCOPIC 
TREATMENT  NOT  PRACTICABLE.  — PRISM  DUC- 
TION  TREATMENT.—  AUTHOR '&  CARDS  FOR  RIGHT 
AND  LEFT  H  YPERPHORIA. 

HYPERPHORIA. 

In  a  few  cases  stereoscopic  treatment  has  been 
attempted  with  revolving  prisms.  The  hyper- 
phoria,  as  indicated  by  cards  B2  and  B3,  is  cor- 
rected by  vertical  prism.  The  ON  NE  card  is  in- 
troduced, and  while  the  patient  holds  the  image 
fused  the  prism  correcting  hyperphoria  is  re- 
duced to  zero,  and  as  much  reverse  prism  used 
as  the  patient  will  endure  without  losing  the 
image.  This  is  a  kind  of  stereoscopic  duction 
and  can  be  repeated  as  many  times  as  thought 
desirable.  The  results  have  not  been  sufficiently 
good  to  warrant  its  continuance. 

In  1908  the  writer  devised  two  new  series 
which  were  published  as  a  supplement  to  the 
first  edition  of  stereoscopic  charts.  These  were 
designed  for  the  treatment  of  hyperphoria.  The 
characters  ON  NE  were  made  of  block  letters 
8  mm.  square,  horizontal  separation  being 


60  STEREOSCOPIC    TREATMENT    OF 

60  mm.  in  all.    Each  set  consists  of  five  cards. 
For  right  hyperphoria  the  right  object  NE  is 
lowered  2,  4,  6,  8,  10  mm.,  corresponding  t<> 
right  hyperphoria  of  2A,  4A,  6A,  8A,  10A.  if  me 
ured  at  10  cm. 


,  AI  ii.  >  -  R  Hypophou  2* 


ON 


(WdU) 


FIG.  19. — DISCONTINUED  SERIES. 

For  left  hyperphoria  the  left  object  ON  is 
lowered  2,  4,  6,  8,  10  mm.,  corresponding  to  left 


JIO  A.  uc.  -  L  HypcfphoiU  10* 


NE 
ON 


(WdU) 


FIG.  20. — DISCONTINUED  SKUII  B, 


HETEROPHOEIA   AND    HETEROTROPIA.  61 

hyperphoria  of  2A,  4A,  6A,  8A,  10A,  if  measured 
at  10  cm. 

The  writer's  idea  was  that  if  a  patient  with 
right  hyperphoria  of  8A  could  fuse  Is  most 
easily,  he  should  be  able  to  progress  to  IG,  14, 
12,  and  thence  to  the  ordinary  cards  with  both 
sides  horizontal.  The  results,  however,  were 
not  satisfactory  even  when  hyperphoria  meas- 
ured with  64  in  stereoscope  at  10  cm.  corre- 
sponded to  hyperphoria  measured  at  5  M. 
Since  no  one  with  whom  the  writer  has  com- 
municated has  had  better  results  with  series  I 
and  J,  they  have  been  omitted  from  the  present 
edition. 

A  stereoscope  might  be  constructed  in  which 
the  spheres  could  be  decentered  vertically  and 
the  same  principle  applied  as  for  training  con- 
vergence and  divergence,  but  of  the  result  the 
writer  is  not  particularly  sanguine. 

Hyperphoria  frequently  disappears  as  the 
convergence  power  increases,  and  if  it  remains 
in  sufficient  amount  to  give  rise  to  symptoms,  it 
is  the  author's  practice  to  correct  it  with  a 
prism,  or  if  of  high  degree  by  tenotomy  or  ad- 
vancement. 


62  STEREOSCOPIC    TREATMENT    OF 


CHAPTER  VII. 

KEOSCOPIC  TREATMENT  OF  HETEROTROPIA.  — OF 
CONCOMITANT  ESOTROPIA.— THE  AMBLYOSCOl'l  . 
—AUTHOR'S  DEVIOMETER.— THI:  I-KKCENTAGE 
OF  CURES.— THE  TIME  FOR  OPERATION. — TREAT- 
MENT OF  ALTERNATING  ESOTROPIA.  — TR1 
MENT  OF  EXOTROPIA. 

ESOTROPIA. 

Ever  since  Worth's  first  publication  in  ilu- 
Lancet,  May  11,  1901,  the  writer  has  been  a  Con- 
scientious follower  of  his  methods.  His  suggea 
tion  of  atropinizing  or  bandaging  the  fixing  eye 
for  months  is  certainly  of  great  value,  and 
although  it  had  been  previously  practiced  by 
Landolt  and  Javal,  Worth  did  well  in  emphasiz- 
ing it  so  forcibly. 

A  certain  number  of  cases  of  concomitant 
esotropia  can  be  cured  by  this  method  ami  tin- 
use  of  the  amblyoscope,  but  this  latter  instru- 
ment has  been  rather  disappointing.  Then-  a  IT 
definite  drawbacks  to  its  practicability.  In  the 
first  place,  one  cannot  see  tin-  child's  eyes  and  is, 
therefore,  forced  to  depend  on  his  statement  as 
to  what  he  sees.  The  imagination  of  the  child 


HETEROPHORIA    AND    HETEROTROPIA. 


63 


is  very  vivid  and  no  one  who  has  tried  to  carry 
out  this  treatment  can  have  failed  to  be  at  his 
"wit's  end"  many  times  to  know  just  what  was 
taking  place.  Then  it  is  absolutely  essential  that 


FIG.   21. — Tin:   AUTHOR'S   DBVIOMETEB   ATTACHMENT    TO  THE 
PEMKKTER. 


the  case  be  seen  early  and  that  the  parent's 
intelligent  cooperation  be  secured. 

Following  Worth's  suggestion  the  writer  de- 
vised a  deviometer  attachment  to  the  perimeter. 
with  which  it  is  possible  to  measure  the  an 
of  the  deviation  in  quite  young  children. 

A  concealed  switch  is  so  arranged  that  the 
central  light,  which  the  child  naturally  fixes,  is 
put  out  at  the  same  instant  the  movable  one  is 
lighted.  Thus,  before  he  has  time  to  change  his 
fixation,  the  reflection  of  the  movable  one  is 
noted  on  the  cornea.  A  few  trials  suffice  to  make 
it  central,  and  the  degree  of  heterotropia  is  read 
off  on  the  arc. 

This  ability  to  make  comparative  measure- 
ments is  an  essential  part  of  the  treatment,  in 
order  to  know  if  the  error  is  getting  les-.  Tin- 
wearing  of  full  correcting  glass  in  the  fixinir 
eye  and  occasional  atropine  in  the  same,  with 
some  less  than  full  correction  of  refraction  for 
suppressed  eye,  will  usually  reduce  the  error 
one-half.  Little  more  than  this  can  be  done  with 
a  very  young  child.  As  soon  as  possible  Worth's 
marble  test  should  be  used  to  get  a  crude  idea 
of  visual  acuity. 

When  the  child  is  able  to  comprehend  the 
amblyoscope,  it  is  given  with  the  simplest  pic- 


HETEROPHORIA    AND    HETEROTROPIA. 


65 


tures  for  home  use,  and  the  phoro-optoraeter 
stereoscope  used  at  the  office.  Fusion  can  often 
be  secured  with  the  latter  in  a  case  needing 
o.  u.  prism  30A  base  out.  Here  we  make  use  of 
Ai  for  left  esotropia,  A2  for  right  esotropia. 


FIG.  22. 


Not  until  concrete  pictures  like  Ci,  €2,  Cs  can 
be  fused  need  one  expect  much  from  stereo- 
scopic exercises. 


FIG.  23. 


66  STKKKOSCOPIC    TREATMENT    OF 

There  is  very  little  holding  power  in  discrete 
pictures,  either  with  the  stereoscope  or  amblvo 
scope,  the  bird  out  of  the  cage  makes  just  as 
pleasing  a  picture  as  the  bird  /'//  tlu-  caire.  Itut 
wlien  the  head  of  C-j  loses  an  eye  or  an  ear, 
one's  sense  of  propriety  is  offended. 

The  prismatic  element  can  be  reduced  by  de- 
centering,  the  same  as  in  treating  euphoria. 
and  the  eyes  may  be  watched  all  the  time  over 
the  top  of  the  instrument  to  note  their  move- 
ments. In  a  favorable  case  the  home  >t« M 
scope  with  as  high  as  o.  u.  15A  base  out  can  In- 
used,  the  amount  Iteing  reduced  a<  condition- 

warrant. 

It   is   somewhat   difficult    to   state   exactly   the 
percentage  of  cures  that   may   he  expected  by 
orthoptic  treatment  alone.     It  is  almost  inn 
sible  to  carry   out  the   full   treatment   with  dis- 
pensary  patients. 

Kmerson,*  of  Orange,  X.  .1..  says:  "In  pri- 
vate practice,  patients  of  good  social  condition, 
who  carry  out  the  treatment  with  intelligence 
and  perseverance,  practically  all  .uvt  well." 

This  statement  is  slightly  ambiguous,  as  it  is 


nf  tin'   M«- lii-iil    Sncicty   nf   \.-\\    .Ii-r-cy."    l!»ll. 


HETEROPHORIA    AND    HETEROTROPIA.  67 

not  stated  in  what  proportion  the  necessary  "in- 
telligence and  perseverance"  are  exhibited. 

Of  all  the  private  cases  of  esotropia  seen  by 
the  writer  during  the  last  five  years  only  twenty- 
five  per  cent,  were  less  than  six  years  old.  Some 
of  these  moved  away  and  were  referred  to  col- 
leagues in  other  cities.  Others  gave  up  the 
treatment  after  a  few  visits. 

Excluding  the  congenital  cases,  nine  per  cent, 
were  given  the  recognized  orthoptic  treatment, 
and  of  these  nearly  three-quarters  were  cured 
and  developed  a  fair  degree  of  binocular  vision. 
A  few  cases  averaging  thirteen  years  of  age 
responded  to  glasses  and  fusion-training  meth- 
ods. Most  of  the  other  cases  were  corrected  by 
advancement  or  advancement  and  tenotomy. 
Post-operative  fusion  training  has  been  used  in 
all  except  those  lacking  all  fusion  sense. 

Since  only  twenty-five  per  cent,  were  less  than 
"six  years  old,  it  is  evident  that  it  is  still  neces- 
sary to  emphasize  the  importance  of  beginning 
this  treatment  early. 

The  intelligent  cooperation  of  the  family  phy- 
sician means  that  he  shall  refer  every  case  to  his 
ophthalmic  surgeon,  whenever  there  is  dis- 
covered even  an  oa-dxioiial  squint.  It  is  true 
that  the  wearing  of  glasses  under  two  years  is 


68  STEREOSCOPIC    TREATMENT    OF 

attended  with  some  difficulty,  but  many  other 
expedients  can  be  used  to  force  the  seeing  with 
the  turned  eye.  These  may  be  atropine  in  the 
fixing  eye  and  an  occlusion  bandage.  Tin- 
object  of  this  very  early  treatment  is  to  preserve 
the  turned  eye  from  amblyopia  exanopsia.  ami 
to  cultivate  the  fusion  faculty  during  those  years 
when  it  is  developing  in  the  normal  child. 

This  treatment  should  be  continued  as  lonu  MS 
the  deviometer  shows  improvement.  This  may 
be  months  or  years,  but  it  is  certainly  a  mistake 
to  delay  operation  too  long.  A  rudiment  of 
fusion  can  often  be  trained  into  a  refined  faculty 
if  the  eyes  are  put  approximately  straight  l>y 
operation. 

The  writer  considers  the  Worth  advancement 
a  very  satisfactory  method,  beginning  with  the 
external  rectus  of  the  esotropic  eye. 

The  one  difficult  part  is  the  introduction  of 
the  scleral  suture.  Instead  of  passing  the  necdlr 
directly  toward  the  pupil,  it  is  passed  parallel 
to  circumference  of  the  cornea,  beginning  each 
one  near  the  median  line.  This  secures  a  firm 
hold  without  encroaching  dangerously  near  the 
anterior  chamber.  This  method  was  in  vogue 
at  Fuchs'  clinic  in  1905.  If  the  convergence  is 
not  sufficient  to  justify  tenotomy  of  the  interims. 


HETEEOPHOEIA   AND    HETEROTROPIA. 


69 


it  is  givren  a  thorough  stretching  (Panas)  before 
the  sutures  are  tied.  If  the  effect  be  insufficient 
the  externus  of  the  other  eye  should  be  advanced 
in  the  same  manner. 


FIG.  24.  —  AUTHOR'S  MODIFICATION  OF  WORTH  ADVANCEMENT. 


ALTERNATING  ESOTROPIA. 

In  these  cases  vision  is  usually  equal  in  the 
two  eyes,  and  there  is  very  little  refractive  error. 


70  STKi;i:«)S(  dl'K      TKKATMKNT    OF 

A  cycloplegic,  or  even  a  slight  blurring  of  either 
eye,  causes  it  to  converge  and  the  other  eye  to 
ti\.  Fusion  faculty  is  usually  nil,  and  any  sort 
of  orthoptic  treatment  generally  of  little  use. 
Advancement  of  both  external  recti  is  usually 
required. 

EXOTROPIA. 

If  occasional,  stereoscopic  treatment  ami 
fusion  training  will  usually  cure  the  exotropia. 
the  method  is  the  same  as  for  exophoria.  The 
result  is  often  orthophoria  by  phorometer. 
Maddox  rod  or  chromatic  test,  but  exophoria 
may  be  still  shown  by  the  screen  test.  As  the 
normal  condition  of  the  individual  is  with  both 
eyes  participating,  it  seems  appropriate  to  u-e 
a  binocular  test,  especially  the  rhromatie.  in 
which  the  tendency  to  hori/ontali/.e  and  verti- 
ealize  is  reduced  to  a  minimum.  This  also  show- 
the  value  of  the  fusion  faculty  in  maintaining 
orthophoria.  If  the  exotropia  exists  all  tin-  time 
immediate  advancement  of  the  internal  rertus. 
followed  by  stereoscopic  training,  is  indicated. 


HETEROPHORIA    AND    HETEROTROPIA.  71 

CHAPTER  VIII. 

THEORIES.  — PSYCHIC  ELEMENT.  — THE  CHOICE  OP 
CARDS. — SUPERABUNDANCE  OF  AMPLITUDE  A 
VALUABLE  RESERVE.  — CONCLUDING  REMARKS. 

A  highly  developed  fusion  faculty,  with  good 
amplitude,  is  essential  to  the  state  called  muscle 
balance.  In  correcting  or  relieving  heteropho- 
ria,  the  first  essential  is  the  development  of  a 
refined  fusion  sense,  if  such  does  not  exist,  or  in 
making  habitual  its  employment  in  the  psychic 
interpretation  of  two  retinal  images. 

The  power  of  a  muscle  depends  not  alone  on 
its  own  physical  properties,  such  as  size,  nutri- 
tion, place  of  attachment,  etc.,  but  also  on  the 
strength  of  the  nervous  stimulus  which  excites 
its  action.  In  discussing  this  subject  in  1902 
the  writer  made  the  following  statement:  "The 
rapid  development  of  adduction  which  is  so 
often  obtained  by  this  so-called  'gymnastics,' 
strongly  suggests  that  the  gain  is  not  a  muscle 
hypertrophy,  but  an  increase  in  innervation, 
either  in  the  responsiveness  of  the  end  organ  in 
the  muscle,  or  the  convergence  center,  or  both." 
In  the  educational  treatment  of  tabes  the  inco- 
ordination  is  overcome  by  teaching  the  patient 


72  STEREOSCOPIC   TREATMENT   OF 

to  gauge  his  motor  impulses  by  the  eye  in  lieu 
of  the  normal  sensory  control.  Repeated  arti- 
ficial contractions  of  the  internal  rectus  (the 
ciliary  remaining  relaxed)  establish  a  habit  of 
increased  action,  so  that  it  no  longer  lags  when 
the  impulse  to  converge  and  accommodate  is  felt. 
The  coordinating  center  may  also  be  taught  to 
1  icttcr  appreciate  the  advantages  of  binocular 
perspective.  This  is  no  special  pleading,  but  is 
analogous  to  other  sensations.  The  pianist 
makes  his  fingers  educate  his  brain  that  the 
brain  may  do  better  work  with  the  fingers.  Tasks 
consciously  performed  are  in  time  relegated  to 
subconscious  control.  If  this  interpretation  of 
muscle  u\  imiastics  be  accepted,  it  is  evident  that 
the  first  indication  is  to  teach  the  patient  the 
fascination  of  true  binocular  fusion.  Just  as  in 
the  ordinary  prism  exercises,  with  the  eye  fi.vd 
on  a  distant  point,  the  aversion  to  diplopia  is 
an  incentive  to  increased  muscle  action,  so  here 
the  fused  image  becomes  an  anchor.  AVith  the 
eyes  fastened  on  a  fused  image,  made  up  of  half 
pictures,  one  strongly  resists  an  impulse  which 
tends  to  pull  it  to  pieces.  The  decentering  of 
plus  10.  lenses  is  a  subtle  means  of  insinuating 
such  an  influence. 
In  all  exercises  of  this  sort  there  is  a  psychic 


HETEROPHOKIA    AND    HETEROTROPIA.  73 

factor  which  should  be  utilized.  Whether  there 
is  or  is  not  a  fusion  center,  there  is  a  fusion 
faculty  which  can  be  cultivated,  in  proportion 
to  the  patient's  attention  and  cooperation. 

To  do  this,  while  the  phoro-optometer  stereo- 
scope is  being  used,  the  patient  should  be 
repeatedly  directed  to  fix  his  attention  on  the 
red  N.  To  help  him  do  this  he  should  be  told  to 
analyze  the  color,  to  decide  just  what  shade  of 
red  it  is,  or  to  fix  his  attention  on  the  oblique 
line  of  the  N.  Other  expedients  will  suggest 
themselves  if  the  importance  of  this  fixation 
of  attention  is  appreciated.  No  distracting 
sounds  should  be  tolerated ;  in  fact,  there  should 
be  no  third  party  in  the  room. 

The  patient  should  also  be  aware  that  the 
oculist  is  thinking  only  of  him,  and  whenever 
any  gain,  however  slight,  is  evident,  as  one 
watches  the  eyes  over  the  stereoscope,  some 
word  of  commendation  should  be  volunteered. 
If  no  such  commendation  should  be  justified,  he 
should  be  encouraged  by  the  suggestion,  "Now 
try  a  little  harder  this  time." 

The  difference  in  the  holding  power  of  differ- 
ent cards  has  been  mentioned.  Formerly  Cs  of 
Javal  was  used.  This  consists  of  separate  let- 
ters L  and  F,  the  fusion  of  which  gives  E. 


74 


A  fter  considerable  experimenting  the  author  de- 
vised the  ON  XE,  the  two  X's  printed  in  red, 
and  believes  this  possesses  the  greatest  holding 
power  of,  anything  yet  produced.  In  the  first 
place  the  word  spells  ONE,  and  when  dis- 
jointed the  <>X  \E  is  meaningless.  More  In- 
ters are  superfluous  and  detract  from  fixation. 
That  there  is  a  subtle  suggestion  in.this,  one  can 
easily  verify  in  the  following  way:  After  the 
card  ON  NK  has  been  used  on  several  occa- 
sions, if  the  prism  is  arranged  so  patient  sees 
arrow  over  6  of  the  card  Bi,  and  if  then  ( ':  i> 
dropped  into  the  clip,  the  patient  will  often  he 
confused,  but  will  be  immediately  relieved  if 
5A  or  10A  more  of  prism  be  turned  up.  This 
shows  that  while  conditions  were  exact  I y  right 
for  easy  fusion  of  Or,  the  instant  that  card  ap- 
peared he  immediately  remembered  what  it  had 
previously  required  and  involuntarily  con- 
verged his  eyes  more  than  was  necessary. 

In  convergence  insufficiency  we  are  dealing 
with  an  incoordination  of  convergence  and  ac- 
commodation. The  nerve  impulse  sufficient  to 
secure  accommodation  is  insufficient  for  conver- 
gence. To  relieve  this  and  to  restore  coordina- 
tion, it  is  necessary  to  incite,  associate  and  to 
make  habitual  a  greater  degree  of  convergence 


HETEROPHORIA   AND    HETEROTROPIA.  75 

with  a  given  amount  of  accommodation.  For 
this  reason  it  has  always  seemed  to  the  writer 
that  exercises  which  brings  into  play  the  accom- 
modation as  well  as  the  convergence  are  illogi- 
cal; e.  £.,  dot  exercises  .or  candle  as  used  by 
Gould. 

With  eyes  fixed  on  a  distant  light,  it  is  as- 
sumed the  accommodation  is  zero,  but  this  is 
difficult  to  verify.  When  emmetropic  eyes  look- 
ing through  plus  10.  lenses  see  clearly  at  the 
focal  distance,  10  cm.,  we  have  proof  that  accom- 
modation is  relaxed  and  it  is  under  these  con- 
ditions that  we  secure  a  very  abnormal  amount 
of  convergence.  To  a  certain  extent  the  same 
is  true  of  the  home  use  of  the  stereoscope  with 
additional  prisms  in  the  clips. 

With  perhaps  one-half  of  one's  successful 
cases,  orthophoria  will  be  secured,  with  the  other 
half  the  heterophoria  will  be  reduced,  but  the 
patient  will  have  secured  such  a  superabund- 
ance of  amplitude  that  he  is  able  to  overcome 
the  wrong  tendencies  automatically  without 
discomfort. 


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